Trust developed in walk (5)
I believe the answer is:
Here is my best explanation:
'walk' is the definition.
(strut is a kind of walk)
'trust developed' is the subsidiary indication.
'developed' indicates anagramming the letters.
'trust' with letters rearranged gives 'strut'.
'in' is the link.
(Other definitions for strut that I've seen before include "Prance", "Trust (anag.)", "Support; walk proudly", "(Walk with) a stiff pompous gait", "Walk proudly like metal support", "Walk proudly like bantam-cock", "Supporting bar", "Walk proudly, swagger", "Support - pompous walk" and "Brace; swagger".)